Diode-pumped Q-switched Tm:YAP laser with a pump recycling scheme

We reported on a diode end-pumped AO Q-switched Tm:YAP laser at 1937 nm. The average output power was 3.9 W, with a slope efficiency of 29.4% and optical-optical conversion efficiency of 21.6% at a 5-kHz repetition rate. The temperature dependency of the output power and the pulse width at different repetition rates were investigated in details.     

Ca2PbGa8O15: Rational Design,Synthesis, and Structure Determination of a Purely Tetrahedra‐Based Intergrowth Oxide

Intergrowth oxides, like Aurivillius, Ruddlesden–Popper phase, comprise functional layers and exhibit interesting physical properties. The hitherto known intergrowth structures mainly were composed of closed‐packing of oxygen ions, and it is very challenging to develop new types of intergrowth structures. We proposed the possible match between the tridymite and grossite, both of which are purely tetrahedra‐based structures. We synthesized Ca₂PbGa₈O₁₅ ((Ca_0.5Pb_0.5Ga₂O₄)₂(CaGa₄O₇)) and its structure was solved by ab‐initio method. Pb²⁺ is vitally important to stabilize this first example of tetrahedra‐based intergrowth oxide. The appropriate size difference between Pb²⁺ and Ca²⁺ causes the layered type cationic ordering, and reduced the thermodynamic potential, in addition, the high hybridization between Pb 6s6p and O 2p orbitals further consolidate the covalency of the tetrahedra‐base framework.     

Finely Controlled Circularly Polarized Luminescence of a Mechano‐Responsive Supramolecular Polymer

Finely controlled circularly polarized luminescence (CPL) supramolecular polymerization based on a tetraphenylethene core with four l ‐ or d ‐alanine branch side chains (l ‐ 1 and d ‐ 1 ) in the solution state is presented, resulting from the tuning of mechanical stimulus. Weak, green emissions of l ‐ 1 and d ‐ 1 in tetrahydrofuran (THF) were converted into strong blue emissions by tuning the mechanical stimulus. The strong blue emissions were caused by an aggregation‐induced emission (AIE) effect during the formation of a supramolecular polymer. Lag time in the supramolecular polymerization was drastically reduced by the mechanical stimulus, which was indicative of the acceleration of the supramolecular polymerization. A significant enhancement of circular dichroism (CD) and CPL signals of l ‐ 1 and d ‐ 1 was observed by tuning the rotational speed of the mechanical stimulus, implying that the chiral supramolecular polymerization was accelerated by the mechanical stimulus.     

Liquid crystal alignment properties on surface-reformed solution-derived lanthanum-doped zinc oxide films

Liquid crystal (LC) alignment characteristics were investigated using a solution-derived lanthanum-doped zinc oxide (La:ZnO) film that was exposed to various intensities of ion-beam (IB) irradiation. At an IB intensity of 1700 eV, uniform and homogeneous LC alignment was achieved, as revealed by cross-polarized optical microscopy and pre-tilt angle measurement. Field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) were used to verify that the IB irradiation induced physical and chemical surface reformation of the La:ZnO film that relate to LC alignment. FE-SEM and AFM revealed that the IB irradiation reformed the existing surface structure into a new structure with an altered surface roughness. The XPS results showed that the van der Waals force with anchoring energy increased as the IB intensity increased, and this profoundly affected the state of LC alignment. The capacitance-voltage (C-V) hysteresis curve was measured as a function of IB intensity to characterize the accumulated charge as a residual DC. Nearly zero C-V hysteresis was achieved at an IB intensity of 1700 eV. Therefore, a solution-derived La:ZnO film with an IB intensity of 1700 eV has great potential for high-quality LC applications.     

Simultaneous quantification of urinary purines and creatinine by ultra high performance liquid chromatography with ultraviolet spectroscopy and quadrupole time‐of‐flight mass spectrometry: Method development,validation, and application to gout study

We present an ultra high performance liquid chromatography with ultraviolet spectroscopy and quadrupole time‐of‐flight mass spectrometry method for the simultaneous quantification of ten purines (adenine, hypoxanthine, guanine, xanthine, deoxyadenosine, adenosine, inosine, guanosine, xanthosine, and uric acid) and creatinine in human urine. After chromatographic separation on an ACE Excel 2 AQ column, high abundant creatinine and uric acid and the other low abundant purines were sequentially detected by ultraviolet and quadrupole time‐of‐flight mass spectrometry within a single run. Method validations including specificity (improved by accurate mass measurement), linearity (correlation coefficients ≥0.9944), limit of quantification (0.002–9.756 µg/mL), intra‐ and interday precision (relative standard deviations ≤9.1 and 14.0%, respectively), accuracy (relative errors ≤13.1%), extraction recovery (between 90.3 and 109.6%), matrix effect (between 85.3 and 110.5%), and stability (relative errors ≤14.3%) were fully evaluated. This approach was applied to characterize the disordered purine metabolism in acute and chronic gout as an example. Quantitative results (normalized by creatinine) showed that an overproduction of urinary purine precursors might be involved in the gout process. The developed method represents a useful tool to investigate the purine disturbances in gout and other relevant diseases.     

Realization of a near-perfect antireflection coating for silicon solar energy utilization

To harness the full spectrum of solar energy, Fresnel reflection at the surface of a solar cell must be eliminated over the entire solar spectrum and at all angles. Here, we show that a multilayer nanostructure having a graded-index profile, as predicted by theory [J. Opt. Soc. Am. 66, 515 (1976); Appl. Opt. 46, 6533 (2007)], can accomplish a near-perfect transmission of all-color of sunlight. An ultralow total reflectance of 1%-6% has been achieved over a broad spectrum, lambda = 400 to 1600 nm, and a wide range of angles of incidence, theta = 0 degrees-60 degrees . The measured angle- and wavelength-averaged total reflectance of 3.79% is the smallest ever reported in the literature, to our knowledge.     

A class of improved algorithms for detecting communities in complex networks

Detecting communities in complex networks is of considerable importance for understanding both the structure and function of the networks. Here, we propose a class of improved algorithms for community detection, by combining the betweenness algorithm of Girvan and Newman with the edge weight defined by the edge-clustering coefficient. The improved algorithms are tested on some artificial and real-world networks, and the results show that they can detect communities of networks more effectively in both unweighted and weighted cases. In addition, the technique for improving the betweenness algorithm in this paper, thanks to its compatibility, can directly be applied to various detection algorithms.     

ESR study of the hydrogenated nanocrystalline silicon thin films

We studied the stability and light-induced paramagnetic centers in hydrogenated nanocrystalline silicon thin films (nc-Si:H) by electron-spin-resonance (ESR) and photothermal-deflection-spectroscopy (PDS). There is no measurable change in defect density upon illumination with white light with a light intensity of 300 mW cm^?2 for 300 h. At low temperatures, upon illumination with sub-bandgap light, a light-induced ESR signal appears. This signal is similar to that in hydrogenated micro-crystalline silicon (μc-Si:H).     

Upper Bound Shakedown Analysis of Plates Utilizing the C1 Natural Element Method

This paper proposes a numerical solution method for upper bound shakedown analysis of perfectly elasto-plastic thin plates by employing the C1 natural element m...